In my (perhaps not so humble
) opinion the cockpit is where we should devote more attention. Well, from the standpoint of a sim pilot, and not a movie maker, anyway.
By concentrating on the 'pit, you bypass an awful lot of time-eating issues with the external model such as smoothing caps, hooks, LODs, etc. I really think the best gain-to-effort ratio (at least as a starting project) would derive from improving cockpits. I've gotten a couple of requests to tackle the Spit 'pit, but other 'pits are currently on my radar. I'm sure you'd get lots of praise were you to take this on.
You start with an SFS extractor utility to get all the cockpit files, and a mesh converter to render the mesh binaries into readable ASCII. How you proceed from there depends on the tools you use. I get by with a spreadsheet for the 3-D modeling and Photoshop for texture work. A very slow way to go about it, but I've gotten to understand the underlying fundamentals much better thereby. For example, I compute the surface normals (which define lighting and shading) myself, knowing the trigonometric framework (such that the sum of the squares of the three vector components always add to make 1.)
As pointed out, starting a full plane from scratch in a first time effort is a heck of a lot more than a few weeks' project. I imagine you'll be at it for perhaps a full year, and that's with a full day's work every week in that interval. Just be aware of the magnitude of the work involved. Hence my recommendation to take on a less ambitious--but extremely worthwhile--project...
Good luck, and hoping to see the fruit of your efforts!